Identification of immune-related biomarkers in adrenocortical carcinoma: Immune-related biomarkers for ACC.

Emerging evidence has suggested that the tumor microenvironment, including immune infiltration, plays a crucially important role in tumor progression. Nevertheless, limited studies have been conducted on this topic in adrenocortical carcinoma. The present study aimed to explore the immune-related biomarkers in adrenocortical carcinoma. CIBERSORT was used to estimate the abundances of 22 kinds of immune cells, and univariable Cox analysis was performed to find survival-related immune cells with both Overall Survival (OS) and Progression-Free Interval (PFI). DESeq2 was applied to find differentially expressed genes between adrenocortical carcinoma and normal control samples; subsequently, weighted correlation network analysis and protein-protein interaction (PPI) network analysis were conducted to identify immune-related hub genes. xCell, TISIDB, and MsigDB were searched to validate the immune associations of hub genes. Eventually, univariable Cox and Kaplan-Meier analysis were used to assess the prognostic implications of the hub gene with the GEO database. Consequently, we identified two hub immune-related genes (ERN1, CEP55), GSEA revealed that both were mainly involved in tumor progression and immune response. ROC analysis indicated that ERN1 can accurately predict the 1-, 3-, and 5-year PFI, and CEP55 had the best performance for the prediction of both OS and PFI compared with other traits. Univariable Cox and Kaplan-Meier analysis showed that both genes have a significant effect on prognosis. Furthermore, both hub genes were validated in GEO datasets. The hub genes can provide better insights into tumor microenvironment and serve as potential biomarkers for immunotherapy in adrenocortical carcinoma.